Eagle Andrew Embley was at the centre of the confusion when he was credited with a goal that would have put his side in front seconds from half time after he soccered through a ball that had appeared to bounce back off the goal post.
However, field umpire Damien Sully ran in to over-rule the goal umpire's decision from the middle of the ground, leading television commentators to believe he had reacted after seeing the replay.
Not so, according to Gieschen.
"Fortunately Damien Sully - the field umpire who was actually in the mid-zone at the time - had a pretty clear and uninterrupted view of the ball skidding towards that post and actually saw it hit the post," Gieschen told Bigpond Sports Weekend on Saturday.
"As soon as he saw the ball hit the post he started to make his way down to let the people know that it had touched the post. On his way through he'd seen that actually confirmed on the big screen as well, so he was 100 per cent certain from what he'd seen and then of course he checked just make sure he was right.
"He was pretty clear-cut to come down and say 'no that ball has hit the post'."
There is currently no provision for video review of incidents during AFL matches with umpires directed not to make any decisions based on replays shown at the ground.
Having spoken with all the game officials involved, Gieschen asserted the right decision had been reached without relying on the replay.
"We ask them to see it with their own eyes before they act on it and he'd actually seen it with his own eyes and that's why he acted on it," he said.
"Had we just looked up at the scoreboard and seen something after it's [happened] - I'm not sure about that.
"The goal umpire at the time wasn't aware that the ball had hit the … post. He thought it had just propped on the line and stayed there which was fairly disappointing from his point-of-view.
"It had actually gone between his legs so there's a fair chance he should have known where that ball had gone."
"[But] we were really pleased that we got the right score out of it because it would have been a pretty obvious mistake had we not corrected that and got it right."
After a closely-contested first half, West Coast went on the win the match comfortably by 35 points.
